public class TestBall {
    public static void playBall(Ball ball){
        ball.playBall();
    }
    public static void main(String[] args) {
        Ball b = new Ball();
        Ball b2 = new Basketball();
        Ball b3 = new Football();
        TestBall.playBall(b);
        TestBall.playBall(b2);
        TestBall.playBall(b3);
    }
}